Riveted the front spar together. This went together pretty easy except I had some minor rubbing on two rivets to the HS00005 rib. I emailed Vans and they said that it should not be an issue since everything it secured tight. I asked if. It would be acceptable to slightly file a bevel in the rivet shop heads and then apply some RTV just in case . They said that was ok and acceptable. So that is what I did. After that I dimpled the skins and attached the left skin. These were my first flush rivets bucked on the entire plane. They didn't come out too bad.